1. Field of the Invention
The present invention relates to a wireless communications device. More particularly, the present invention relates to an apparatus and a method of optimizing the power saving in a wireless communications device.
2. Description of Related Art
As more and more current electronic gadgets become mobile, demand for mobile or wireless internet accesses anywhere and anytime increases. Accordingly, wireless internet or intranet accesses may surpass the traditional wired internet access in a very near future. In cities that offer a city-wide free or very cheap wireless internet access, such as a hot spot, the future may have been realized earlier. People with a laptop, personal data aid (PDA) or even a wireless mobile phone can access the internet via a mobile telecommunications networks, wireless local area network (WLAN) access points such as IEEE 802.11 or Bluetooth. Although the mobile telecommunications networks may provide the mobile terminals with a consistent, extensive coverage for the internet access, it may be still more expensive and slower than using the WLAN or Bluetooth. As long as the user has a prearranged subscription to the hot spots, the user of the mobile terminal such as the laptop, the mobile phone or PDA may access the internet with a relatively high communication speed. Accordingly, the mobile terminal using WLAN may provide the user with cheaper cost for data and/or voice communication and faster, higher data rate than the regular mobile terminal using the mobile telecommunications networks. A Voice-Over-Internet-Protocol (VOIP) can be one of most popular application for the mobile with WLAN feature.
However, the VOIP on the mobile terminal may have several shortcomings. First, because the WLAN is usually specified for a personal computer and does not usually require a handover, the mobile terminal with the WLAN/Bluetooth feature may experience when used for VOIP. If a user of the mobile terminal moves outside the coverage area of the WLAN hotspot, any call made by the VOIP can lose the connection due to a lack of handover from the WLAN to other wireless network, such as mobile telecommunications network. Conversely, the general mobile telecommunications network, such as GSM/GPRS/UMTS, has been optimized for the handover and power consumption thereof.
Currently, the solution for the mobile terminal to recognize if it is at or near a WLAN cell or hotspot is to detect the entire band periodically. As the mobile terminal may have to constantly check if it is within the hot spot using its radio transceiver, the power consumption of the mobile terminal may substantially increase. Since the most mobile terminals are battery-powered, the reduction of the battery life can undercut the effectiveness of the true mobility of the mobile terminal. If the user does not want the mobile terminal to automatically scan the WLAN cell or coverage area, the user may have to manually select the WLAN communication when he or she needs it. With this strategy, the use of the WLAN capable mobile terminal is not automatic and not user-friendly.